What a cat shouldn't do

My cat Thor is a real sweetheart and like most cats, an adventurer. I have two containers of water that I leave out on my art table for cleaning my brushes while I am painting. My cats have never bothered my stuff before, but I recently moved my art table and easel to a different room in my house. All of a sudden, he and one of my other cats became interested in what was on my art table. He found the water container and decided to drink out of it. Not the brightest idea he has ever had. Three barfs later... all is well. I now cover the water container.